Dr Tony Van Loon of the Free University of Brussels said: "From the 35 patients who died from euthanasia, the relatives and the doctors performing euthanasia explicitly reported many had a calm and smooth passing.

"Mostly the procedure took place in domestic surroundings with their family and or friends present at the time of the death."

In 2010 and 2011, 2,086 patients died by euthanasia in Belgium, accounting for 1% of all deaths during that period.

Those who were not terminally ill made up less than 10% of that total.